Op de Beeck Hans P, Deutsch Jennifer A, Vanduffel Wim, Kanwisher Nancy G, DiCarlo James J
McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Cereb Cortex. 2008 Jul;18(7):1676-94. doi: 10.1093/cercor/bhm196. Epub 2007 Nov 21.
The inferior temporal (IT) cortex in monkeys plays a central role in visual object recognition and learning. Previous studies have observed patches in IT cortex with strong selectivity for highly familiar object classes (e.g., faces), but the principles behind this functional organization are largely unknown due to the many properties that distinguish different object classes. To unconfound shape from meaning and memory, we scanned monkeys with functional magnetic resonance imaging while they viewed classes of initially novel objects. Our data revealed a topography of selectivity for these novel object classes across IT cortex. We found that this selectivity topography was highly reproducible and remarkably stable across a 3-month interval during which monkeys were extensively trained to discriminate among exemplars within one of the object classes. Furthermore, this selectivity topography was largely unaffected by changes in behavioral task and object retinal position, both of which preserve shape. In contrast, it was strongly influenced by changes in object shape. The topography was partially related to, but not explained by, the previously described pattern of face selectivity. Together, these results suggest that IT cortex contains a large-scale map of shape that is largely independent of meaning, familiarity, and behavioral task.
猴子的颞下（IT）皮质在视觉物体识别和学习中起着核心作用。先前的研究在IT皮质中观察到对高度熟悉的物体类别（如面孔）具有强烈选择性的斑块，但由于区分不同物体类别的众多属性，这种功能组织背后的原理在很大程度上尚不清楚。为了将形状与意义和记忆区分开来，我们在猴子观看最初新颖的物体类别时，用功能磁共振成像对它们进行扫描。我们的数据揭示了IT皮质中对这些新颖物体类别的选择性地形图。我们发现，这种选择性地形图具有高度的可重复性，并且在3个月的时间间隔内非常稳定，在此期间，猴子接受了广泛的训练，以区分其中一个物体类别的示例。此外，这种选择性地形图在很大程度上不受行为任务和物体视网膜位置变化的影响，这两者都保留了形状。相比之下，它受到物体形状变化的强烈影响。该地形图与先前描述的面孔选择性模式部分相关，但不能用其解释。总之，这些结果表明，IT皮质包含一个大规模的形状图谱，该图谱在很大程度上独立于意义、熟悉程度和行为任务。
